Revit MEP

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Member
smart_guy7989
Posts: 4
Registered: ‎10-21-2013
Message 1 of 4 (152 Views)

CLTD , and LM tables that Revit MEP use .

152 Views, 3 Replies
03-05-2014 06:44 AM

 I would like to use Revit in design, but I found some differences between my manual calculations and the software results, like the U factor calculations for wall elements and the reason that Revit do not use resistance for inside and outside film of the wall ( lets say we can pass this problem and defined a wall as group A,B,C...ets) in heating and cooling loads I got the exact values from Revit same as it in my manual calculations, but I did not got it for cooling calculations. Cooling calculations contain factors like CLTD ,LM , where these values not appear for users. I controlled the inputs of Revit to get judge at results or to get the results, I couldn't.

Can anyone give me the tables of CLTD and LM that use in cooling loads , or have an idea what the refference of it .

 

Valued Contributor
russellvee
Posts: 52
Registered: ‎04-22-2013
Message 2 of 4 (129 Views)

Re: CLTD , and LM tables that Revit MEP use .

03-05-2014 09:47 AM in reply to: smart_guy7989

I could be wrong but Revit uses the RTS method and I believe the Latitude-Month (LM) factor is used in the older CLTD/CLF method. What method are you using for your manual calculations? For the RTS calculations, I believe CLTD is determined by the peak temp for each month in the weather tables minus your interior setpoint, and latitude for solar gain is set by your site latitude under the location tab.

Member
smart_guy7989
Posts: 4
Registered: ‎10-21-2013
Message 3 of 4 (123 Views)

Re: CLTD , and LM tables that Revit MEP use .

03-05-2014 09:59 AM in reply to: russellvee
Dear Russel thanks for your answer , Could you please give me the full name
of the RTS method, to read about. And I wonder if you have account at
LinkedIn.
Valued Contributor
russellvee
Posts: 52
Registered: ‎04-22-2013
Message 4 of 4 (119 Views)

Re: CLTD , and LM tables that Revit MEP use .

03-05-2014 10:28 AM in reply to: smart_guy7989

RTS = Radiant Time Series method

 

Here is a PDF article from ASHRAE describing it:

https://www.ashrae.org/File Library/docLib/Public/20031229141126_266.pdf

 

Sorry I don't use linkedin.

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